Chlorine dioxide is used for bleaching a variety of materials, including wood pulps. Chlorine dioxide conveniently is formed by reduction of sodium chlorate in an acid aqueous reaction medium and the chlorine dioxide is evolved as a gas. The gas then is absorbed in water using absorption towers to form an aqueous solution for use.
Chlorine dioxide undergoes spontaneously decomposition when present at high partial pressures in the gas phase and steps are taken, during the production of chlorine dioxide, to dilute the gas phase to inhibit such decomposition. However, localized high partial pressures of chlorine dioxide inevitably occur in the gas space of commercial chlorine dioxide generators, leading to the formation of what are termed "puffs", or localized decompositions of chlorine dioxide, which is undesirable since such puffs result in a decreased yield of chlorine dioxide.